Merge pull request #631 from laurynas-biveinis/gsl-cmake

 Handle GSL dependency as a full CMake subdirectory instead of a C++ include dir

CMakeLists.txt

@@ -345,6 +345,8 @@ else()
   set(USE_BOOST_STACKTRACE OFF)
 endif()
 
+add_subdirectory(3rd_party/GSL)
+
 string(REPLACE ";" " " CXX_FLAGS_FOR_SUBDIR_STR "${SANITIZER_CXX_FLAGS}")
 if(MSVC)
   string(REPLACE ";" " " MSVC_WARNING_FLAGS_FOR_SUBDIR_STR_TMP "${MSVC_CXX_WARNING_FLAGS}")
@@ -601,7 +603,6 @@ if(IWYU OR MAINTAINER_MODE)
 endif()
 
 set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
-set(GSL_INCLUDES "3rd_party/GSL/include")
 
 function(COMMON_TARGET_PROPERTIES TARGET)
   cmake_parse_arguments(PARSE_ARGV 1 CTP "SKIP_CHECKS" "" "")
@@ -681,14 +682,14 @@ endfunction()
 function(ADD_UNODB_LIBRARY LIB)
   add_library(${LIB} ${ARGN})
   common_target_properties(${LIB})
-  target_include_directories(${LIB} SYSTEM PUBLIC "${GSL_INCLUDES}")
+  target_link_libraries(${LIB} PUBLIC Microsoft.GSL::GSL)
   set_clang_tidy_options(${LIB} "${DO_CLANG_TIDY}")
 
   if(LIBFUZZER_AVAILABLE)
     set(LIB_LF "${LIB}_lf")
     add_library(${LIB_LF} ${ARGN})
     common_target_properties(${LIB_LF} SKIP_CHECKS)
-    target_include_directories(${LIB_LF} SYSTEM PUBLIC "${GSL_INCLUDES}")
+    target_link_libraries(${LIB_LF} PUBLIC Microsoft.GSL::GSL)
     target_compile_options(${LIB_LF} PRIVATE "-fsanitize=fuzzer-no-link")
   endif()
 endfunction()